Nowadays, most cars have a switch for a vehicle (hereafter referred to as a switch) mounted in car doors to control switching of room lights or to detect locking of doors according to opening/closing of the doors.
The switch is typically covered with rubbers for waterproofing as the switch is mounted in a position of a door subject to getting wet by raindrops or the like when the door is open.
The conventional switch is described with reference to FIGS. 5 and 6. FIG. 5 shows a cross-sectional view of a conventional switch. FIG. 6 shows car 40 as an example of a vehicle.
An upper portion of substantially cylindrical shaped inner case 2 made of insulation resin is fitted securely into substantially cylindrical shaped outer case 1 made of insulation resin as shown in FIG. 5. Stationary contacts 3 and 4 made of conductive metal are disposed facing each other on right and left hand side inner wall surfaces of inner case 2. Substantially U-shaped movable contact 6 made of conductive metal is mounted on operating body 5. Both ends of movable contact 6 attach to stationary contacts 3 and 4 resiliently. Movable contact 6 thus forms a switching-element to connect/disconnect stationary contacts 3 to 4 electrically.
Rubber cap 7 is disposed on the top surface of outer case 1 covering the top of operating body 5 that protrudes out of an aperture of outer case 1 to prevent raindrops from coming into gaps between the aperture and operating body 5. Coiled spring 8 is mounted between the bottom surface of operating body 5 and the base surface of inner case 2 in a slightly sagging condition, causing operating body 5 to be biased upward.
The top ends of a plurality of conductive metal lead wires 9 coated with insulation resin or the like are connected to the bottom ends of stationary contacts 3 and 4 that extend out of the bottom surface of inner case 2 via conductive metal connector 10.
While the upper portion of rubber cover 11 placed in contact with the periphery of the lower portion of outer case 1 covers the bottom ends of stationary contacts 3 and 4, the top ends of lead wires 9 and connector 10, lead wires 9 that have been pressed into the bottom surface of cover 11 extend downward.
Namely, cover 11 covers the bottom ends of stationary contacts 3 and 4 extending out of the bottom surface of inner case 2, the conductive portion of connector 10 or the like that couples stationary contacts 3 and 4 with lead wires 9, and slight gaps of the fitting portion of inner case 2 to outer case 1. The conductive portions of the switch are thus protected from moisture condensation or water infiltration.
The switch is mounted in door part 20 of car door 30, with bottom ends of lead wires 9 being connected to electronic circuits (not shown) of car 40.
Upon closing car door 30, door part 20 pushes the top of operating body 6 while depressing cap 7 causing operating body 5 to move downward while depressing spring 8.
Then both ends of movable contact 6 mounted on operating body 5 depart from stationary contacts 3 and 4, and attach right and left hand side inner wall surfaces of inner case 2 resiliently, causing the switching-element to open and for instance room lights turn off.
On the other hand, upon opening car door 30, door part 20 releases operating body 5 from the pushing force. Subsequently, a biasing force of spring 8 moves movable contact 6 upward with operating body 5, causing both ends of movable contact 6 to contact stationary contacts 3 and 4 resiliently, thereby causing the switching-element to close and for instance room lights or the like turn on.
As aforementioned, the switch configuration has a function capable of controlling room lights or the like or checking door locking according to opening/closing detection of car doors.
Japanese Patent Unexamined Application No. 2003-146077 discloses the switch with such a configuration.
In the conventional technology, however, while cap 7 that has no vent is depressed, operation air trapped in cap 7 is compressed as the switch is sealed air-tight internally by cap 7 and cover 11. As a result, the drawback is that the switch cannot operate in quick response, and cap 7 and operating body 5 are apt to return unstably after the pushing force is released.
The present invention aims at solving the conventional problems and can provide a switch with an excellent operating feeling and stable switching performance.